Thozalinone as an antiparkinson agent

ABSTRACT

This disclosure describes a method of controlling the tremor and rigidity of Parkinson&#39;&#39;s disease or a drug-induced extrapyramidal disorder in a mammal which is afflicted with said disease or disorder which comprises administering thozalinone or anionic salts thereof to said mammal.

United States atent Gray et a]. 1 May 23, 1972 [54] THOZALINONE AS AN ANTI- References Cited PARKINSON AGENT UNITED STATES PATENTS Inventors: William David Gray, New City, 3,037,990 6/1962 Hardy et a1. ..260/307 Charles Edward Raul, Ni 3,313,688 4/1967 Hardy et al. ..424 272 [73] Assignee: American Cyanamid Company, Stamford,

Conn. Primary Examiner-Stanley J. Friedman [22] Filed: Aug 7, 1970 Attorney-Edward A. Conroy, Jr

[21] Appl. No.: 62,181 [57] ABSTRACT This disclosure describes a method of controlling the tremor [52] U.S.Cl. ..424/272 and rigidity of Parkinson's disease or a drug induced i235 ..424 272 "apymmidal disorder in a mammal which is amicted with Said disease or disorder which comprises administering thozalinone or anionic Salts thereof to said mammal.

3 Claims, No Drawings THOZALINONE AS AN ANTI-PARKINSON AGENT BRIEF SUMMARY OF THE INVENTION This invention relates to a novel method of controlling the symptoms of Parkinson's disease or a drug-induced extrapyramidal disorder in mammals, especially a human being, which comprises administering thozalinone to said mammals afflicted with said disease or disorder. Thozalinone (2- dimethylamino--phenyl-2-oxazolin-4-one) is a known central nervous system stimulant and is represented by the following structural formula:

0 CgHsT INKCHQ:

Thozalinone free base forms acid-addition salts with a variety of non-toxic pharmaceutically acceptable salt forming reagents. Thus, acid-addition salts, formed by admixture of the free base with an acid in a suitable inert solvent, are formed with such acids as sulfuric, phosphoric, hydrochloric, hydrobromic, and related acids. For purposes of this invention, thozalinone free base is equivalent to its pharmaceutically acceptable acid-addition salts.

BACKGROUND OF THE INVENTION Parkinsons disease is described as a syndrome of progressive rhythmic tremor, masklike facial expressions, slowing of movements, with increasing rigidity coming on in the fifth or sixth decade, called paralysis agitans or shaking palsy. In both Parkinson's disease and drug-induced extrapyramidal disorders, the patient exhibits one or more of the following symptoms: tremor, rigidity, increased salivation, akathisia, manifested by extreme restlessness, and dyskinesias, characterized by spastic contractions and involuntary movements.

The drugs most widely prescribed for use in the treatment of Parkinson's disease and drug-induced extrapyramidal disorders are 3-( l-pyridyl)-l-phenylcyclohexyl-l-propanol hydrochloride and l-dopa [3-(3,4-dihydroxyphenyl)-L- alanine]. Unfortunately, these agents and the other currently available agents for treatment of Parkinson's disease possess side effects which limit their use. Thozalinone, on the other hand, is free from peripheral cardiovascular effects and is far less expensive than l-dopa. Many of the patients afflicted with Parkinson's disease are refractory and do not respond favorably to treatment with any of the presently available agents so that, obviously, additional agents such as those of the present invention are needed.

In the last few years several reports have indicated that the brain levels of dopamine, norepinephrine, and serotonin are lowered in Parkinsons disease [Ehringer and Homykiewicz, Klinische Wochenschrift 38(24): l,2361,239, (Dec. 1960); Bernheimer, Birkmayer, and Hornykiewicz, Klinische Wochenschrift 4l( 465-469 (May 1963); Hornykiewicz, Wiener Klinische Wochenschrift 75(18): 309-312 (May 1963)]. In more than 40 patients who died with Parkinson's disease (postencephalitic and idiopathic), the greatest reduction was found in striatal and nigral dopamine [Homykiewicz, Metabolism of brain dopamine in human parkinsonism; neurochemical and clinical aspects. In: Biochemistry and Pharmacology of the Basal Ganglia. Proceedings of the Second Symposium of the Parkinsons Disease Information Research Center, College of Physicians and Surgeons, Columbia University, New York, 1965, E. Costa, L. J. Cote and M. D. Yahr, eds. Hewlett, N. Y. Raven Press, 1966, pp 171-185].

DETAILED DESCRIPTION OF THE INVENTION It has now been discovered that the administration of thozalinone or salts thereof to mammals has a marked effect on the synthesis of dopamine in the brain. Thozalinone, as opposed to dextro-amphetamine, causes a marked increase in the synthesis of dopamine in the brain. Thozalinone is thus superior to dextro-amphetamine which has been used for the treatment of Parkinsons disease. Thozalinone may be administered orally or parenterally in amounts ranging from about 0.1 mg. to about 20 mg. per kg. of body weight per day in the form of the free base or as non-toxic acid addition salts thereof for the treatment of Parkinsons disease. A preferred dosage regimen for optimum results would be from about 0.5 mg. to about 5 mg. per kg. of body weight per day, and such dosage units are employed that a total of from about 25 mg. to about 250 mg. for a subject of about 50 kg. body weight are administered in a 24 hour period. The dosage regimen can be adjusted to provide the optimum therapeutic response. For example, several doses of 50-100 mg. may be administered per day.

Thozalinone and its non-toxic acid-addition salts may be orally administered, for example, with an inert diluent or with an assimilable edible carrier, or they may be enclosed in hard or soft gelatin capsules, or they may be compressed into tablets, or they may be incorporated directly with the food of the diet. For oral therapeutic administration, the active compounds of this invention may be incorporated with excipients and used in the form of tablets, troches, capsules, elixirs, suspensions, syrups, wafers, chewing gum, and the like. Such compositions and preparations should contain at least 0.1 percent of active compound. The percentage in the compositions and preparations may, of course, be varied and may conveniently be between about 5 percent to about 75 percent or more of the weight of the unit. The amount of active compound in such therapeutically useful compositions or preparations is such that a suitable dosage will be obtained. Preferred compositions or preparations according to the present invention are prepared so that an oral dosage unit form contains between about 5 and 250 milligrams of active compound.

The tablets, troches, pills, capsules and the like may also contain the following: a binder such as gum tragacanth, acacia, corn starch or gelatin; an excipient such as dicalcium phosphate; a disintegrating agent such as corn starch, potato starch, alginic acid and the like; a lubricant such as magnesium stearate; and a sweetening agent such as sucrose, lactose or saccharin may be added or a flavoring agent such as peppermint, oil of Wintergreen, or cherry flavoring. When the dosage unit form is a capsule, it may contain in addition to materials of the above type a liquid carrier such as a fatty oil. Various other materials may be present as coatings or to otherwise modify the physical form of the dosage unit, for instance, tablets, pills or capsules may be coated with shellac, sugar, or both. A syrup or elixir may contain the active compounds, sucrose as a sweetening agent, methyl and propyl parabens as preservatives, a dye and a flavoring such as cherry or orange flavor. Of course, any material used in preparing any dosage unit form should be pharmaceutically pure and substantially non-toxic in the amounts employed.

Compositions having the desired clarity, stability, and adaptability for parenteral use are obtained by dissolving from 0.10 percent to 10.0 percent by weight of thozalinone or its salts in a vehicle consisting of a mixture of non-volatile, normally liquid polyethylene glycols which are soluble in both water and organic liquids and which have molecular weights of from about 200 to about 1,500. Such mixtures of polyethylene glycols are commercially available and are usually obtained by condensing glycol with ethylene oxide. Although the amount of thozalinone or salt thereof dissolved in the above vehicle may vary from 0.10 to 10.0 percent by weight, it is preferred that the amount employed be from about 3.0 percent to about 9.0 percent by weight. Although various mixtures of the aforementioned non-volatile polyethylene glycols may be employed, it is preferred to use a mixture of non-volatile polyethylene glycols having an average molecular weight of about 400. Such a mixture is usually referred to as polyethylene glycol 400. A preferred embodiment comprises a clear solution of from about 3.0 percent to about 9.0 percent by weight of thozalinone dissolved in an aqueous solution of polyethylene glycol 400. In addition to thozalinone or salts thereof, the parenteral solutions may also contain various preservatives which may be used to prevent bacterial and fungal contamination or chemical degradation.

Thozalinone and dextro-amphetamine were compared at equi-stimulant doses, 30 mg./kg. and 3 mg./kg. intraperitoneally being about the median excitant doses, respectively. Doses of 100 mg./kg. of thozalinone and mg./kg. of dextro-amphetamine are considered to be excessive. This comparison was carried out in a twofold manner. Firstly, to establish whether steady-state conditions prevailed following drug treatment as measured by pool size (concentration) of amines in brain, and secondly, to measure the efiect of these two drugs under steady-state conditions on the synthesis of norepinephrine and dopamine in brain, measured by effect on catecholamines in the brain of warm-blooded mammals.

Dextro-amphetamine caused a significant depletion of norepinephrine at 10 mgjkg. and significantly increases the concentrations of dopamine at 3 mgJkg. Steady-state conditions for norepinephrine and dopamine prevailed at the doses of thozalinone used and for norepinephrine and dopamine at 3 and 10 mg./kg., respectively of dextro-amphetamine.

Thozalinone at the doses used and dextro-amphetamine at 3 mg./kg. have no significant effect on the pool size, turnover rate or turnover time of norepinephrine. Because of the absence of steady-state conditions, measurements of the effect of 10 mg./kg. of dextro-amphetamine on turnover time and rate of norepinephrine could not be made. For the same reason, the effect of 3 mg./l g. on dopamine turnover time and rate could not be measured. At 10 mg./kg. of dextroamphctamine, there appeared to be a decrease in turnover time and an increase in the turnover rate of dopamine, but the changes were not statistically significant. In contrast thozalinone very markedly decreases the turnover time and increases the turnover rate of dopamine in the brain of warmblooded mammals at mg./kg. and 100 mg./kg. Turnover rate refers to the renewal of a substance in the body or in tissue during steady-state conditions. Renewal may be accomplished by synthesis in the tissue or exchange between the circulation and the tissue. Because both circulating dopamine and norepinephrine are excluded from the brain by the bloodbrain barrier, turnover rate in this study refers to synthesis.

of light during a five minute session in the activity chamber. Counts .were recorded on a digital counter connected to the photocell unit. The top of the chamber was covered so that external visual stimuli would be kept homogeneous. A total of five groups of five mice each were used on each treatment to provide sufficient data for statistical comparison. Each group of five mice was housed in individual 14 X 20 cm. rectangular wire cages for at least 4 hours prior to their session in the actophotometer. In all experiments motor activity was recorded 30 minutes after intraperitoneal administration of damphetamine, thozalinone or control (water). Control and drug treated animals were run in parallel. The results appear in Table 1 below.

Measurement of Brain Amines Those groups of five mice used for recording motor activity were immediately removed from the activity counter and sacrificed by cervical fracture. The brains were removed, weighed, quick frozen and stored at C. until assayed. in the determination of norepinephrine and dopamine, tissues were extracted by a modification of the method of Shore and Olin, J. Pharmae. Exp. Ther. 122: 295-300 (1958), which modification was described by Gray and Rauh, J. Pharmac. Exp. Ther. 155: 127-134 (1967). Brain amine concentrations were determined spectrophotofluorometrically. The method of Maynert and Klingman, J. Pharmac. Exp. Ther. 135: 285-295 (1962) was used for the measurement of norepinephrine and the method of Carlsson and Waldeck, Acta physiol. scand. 44: 293-298 (1958) was used to measure dopamine. Three pooled mouse brains were assayed, using the same aliquot of homogenate for the determination of both monoamines. The results appear in Table 1 below.

At essentially equi-stimulant doses, thozalinone difiered from dextro-amphetamine in having no action on the concentrations of norepinephrine and dopamine in brain, i.e. steadystate conditions prevailed at both doses of thozalinone for norepinephrine and dopamine; for dextro-amphetamine steady-state conditions existed for norepinephrine at 3 mg./kg. and at 10 mg./kg. for dopamine. At the present time no functional significance can be attached to the increase in the pool size (concentration) of dopamine in brain after 3 mg./kg. of dextro-amphetamine or to the depletion of norepinephrine in brain after the administration of 10 mgJkg. of this agent.

TAB LE I Norepinephrine Dopamine Motor activity Concentration, Change, Concentration, Change, Count Change, Treatment mcg./gm. percent meg/gm. percent (5 min.) percent Water 0. 362:1:0. 04 0. 65210. 03 578i38 d-Amphetamine, 3 mgJkg. 0. 370=l;0. 04 +2 n 0. 770:1:0. 05 +18 e 8613;160 +49 d-Amphetamine, l0 mg.,/kg 0. 30210. 02 17 0. 655:1:0. O4 0 3 739115170 +28 'Illozalinone, 30 mgJkg 0. 359ziz0. 05 1 0. 68l;l;0. 12 +4 852:1;62 +47 Thozalinone, 100 lug/kg 0. 365:1;0. 03 +1 (170510.04 +8 b 908:1;109 +73 =Different from control at p'Z0.05.

b =Different from control at 120.01.

Brain amine concentrations are means :1: standard deviations of a samples of 3 brains each (15 mice). Motor activity was measured in 5 groups of 5 mice each per dose level. Positive values mean an increase and negative values mean a decrease from control.

EXAMPLE 1 Effect of d-Amphetamine and Thozalinone on Brain Amine Concentration and Motor Activity of Grouped Mice Motor Activity:

A circular actophotometer (Metro Industries, Long lsland City, New York), 12 inches in diameter and containing six photocell units, was employed. The measure of activity was EXAMPLE 2 Effect of Dextro-amphetamine and Thozalinone on Norepinephrine and Dopamine Pool Size and Turnover The turnover rate of norepinephrine and dopamine was calculated according to the steady-state kinetics [Brodie et al., J. Pharmac. Exp. Ther. 154: 493-498 (1966)] from the endogenous norepinephrine or dopamine level and from the decline in the level of these amines 3 hours after their synthesis was blocked by a-methyltyrosine (AMT). d-Amphetamine (3 and 10 mg./ltg.), thozalinone (30 and 100 mg./kg.) or control vehicle were administered to groups of 15 mice each, 30 minutes prior to a single dose (200 mgjkg.) of AMT. Three hours after AMT administration the norepinephrine and dopamine content of whole brain was determined. In itial amine pool sizes (control levels) were obtained from addithe number 0f times that five mice crossed the CI'OSSfid beams tional groups 0f mice which received only the timulants o vehicle and were sacrificed 30 minutes later. In each instance, The sorbitol solution is added to 40 ml. of distilled water brains of three mice were pooled and norepinephrine and and the active ingredient is suspended therein. The sucaryl, dopamine were extracted and assayed by the methods saccharin, sodium benzoate, flavor and dye are added and disdescribed in Example 1. The results appear in Table II below. solved in the above solution. The volume is adjusted to 100 Assessed by turnover rates and times, thozalinone at the doses 5 mlh distilled Waterused had no effect on the synthesis of norepinephrine but ig- Other ingredients may replace those listed in the above fornificantly increased the synthesis of do amine, Dextromulation. For example, a suspending agent such as bentonite amphetamine, on the other hand, under steady-state condimagma, "agacamh, cal'boxymethylcenulose or methylcellu' tions had no statistically significant effect on the synthesis of 1056 y be used- Phosphates. cill'ales r lanrates y be the two catecholamines, Po ibl at 10 /k d 10 added as buffers. Preservatives may include the parabens, soramphetamine increased th th i f d i to some bic acid and the like and other flavors and dyes may be used in degree. place of those listed above.

TABLE II Norepinephrine Dopamine Motor activity lool size, Turnover Turnover rate, lool size, Turnover Turnover rate, counts/ Treatment nice/g. time, hours nicg./g./hr. meg/g. time, hours incg./g./hr. min.

(Jmitmi (vehicle) .300 (331F381)... 5.2 (-l.30.5)... .070 (0554185)... .035 .5.12-.681)..... 5.5 (3340a).. .115 (.007-.i03) 578i3g Amphetamine, 3 mg./kg. l.l.. 360 (333* 400)... .3 (5.54.4)... .050 (0101078)... .813"(.65l)l.002) 8Gl" 60 Alllpllltulllllli, 10 mgJkg. l.l 300 (BTU-.312) .712 (577-878).. 3.5 (3.0-4.3)... .201 (.1l7.285).. 430*:170 Thozalinone, 30m ./k 1.1 303 (eras-.435)... 5.0 (4.5-5.8)... .078 (.057'c00) .740 (.605-..ll!l) 3.2 (21933) .231(.13l.323) 852 462 Tllozalinone, 100 nigh/kg. 1.1 .302 (.35i-.-13i). 5.1 (1.658)... .076 (055.007)... .700 (.575-.s74).... 2.6 (2.3-2.0)... .277 (181-373).... 008 :109

Level of significance when compared with vehicle control: P204; 'I=.01; P=.05; l=.002; l=.( )1. I v I The amine parameters are the means and 05% confidence limits of 5 samples of 3 mice each (15 mice). Motor activity is the mean 5 minute count 8.1).) for 5 group 015 mice each Amphetamine, thozalinonc or vehicle was administered hr. prior to AMT (200 mg./kg. LP.) or sacrifice; mice which received AMT were sacrificed 3 hrs. later.

The concentrations of amines are probably only significant to two decimal places.

Because steady-state conditions do not prevail, turnover times and rates could not be calculated for dopamine and norepincphrine after 3 and 10 nig./ kg, respectively, 01 (lextioaniplietainine.

EXAMPLE 3 EXAMPLE 5 3O [Pmpamnon of tablet formulation] Preparation of Parenteral Formulation Per For 10,000 Ingredient tablet (g.) tablets (g) In a solution of 119 ml. of propylene glycol and ml. of Active ingredient: 2 dimethymmin0 5 distilled water was dissolved 8.5 g. of 2-dirnethylamino-5- phenyl-z-oxazolin-i-one 5 0 500 phenyl-2-oxazohn-4-one hydrochloride, with stirring. After Lactose 0.0800 800 corn starch (for mix) 0150 150 dissolution was complete, a solution of 850 mg. of sodium for- Corn starch (for paste) 1 1 maldehyde sulfoxylate in 3.0 ml. of distilled water was then Totl 0.1550 1, 550 added to the formulation. The pH of this solution was then adjusted to 7.0 with ethanolamine and the volume was made up .\hignc:iiini st Hunt) 1? 0. 0013 12. 5

i L aa 40 to 170 ml. with distilled water. The formulation was filtered Total 0. 1563 1, 562. 5

through a fine sintered glass filter, filled into 5.0 m1. ampoules each containing 2.0 ml., and sealed under nitrogen.

The active ingredient, lactose and corn starch (for mix) are We Claim: blended together. The corn starch (for paste) is suspended in 800 milliliters of water and heated with stirring, to form a The method of wmrolling the tremor and rigidity of paste. This paste is then used to granulate the mixed powders. kinsons diseas? or drug'induced extliapyliamidal disofdel' in Additional water is used, if necessary. The wet granules are a mammal whlch amlcted Wlth 531d dlsease dlsordel' passed through a No. 8 hand screen and dried at 120 F. The which comprises administering Orally to Said mammal an dry granules are then passed through a No. 16 screen. The fective amount of a Compound Selected from the group mixture is lubricated with 1 percent magnesium stearate and i ing f 2-dimethylamino-5-phenyl-2-oxazolin-4-one and a compressed into tablets in asuitable bl i hi pharmaceutically acceptable acid-addition salt thereof in association with a pharmaceutical carrier to provide a daily dosage of from about 0.1 to about 20 milligrams per kilogram [Preparation of oral syrup formulation] of body weight of the mammal.

EXAMPLE 4 Ingredient Amount 2. The method as defined in claim 1 wherein the compound Active ingredient: ZZ-dimethylamino- 5 phenyl 2 0mzonn 4omy mgm 1,000 18 2 dimethyl amino 5 phenyl 2 oxazolin 4 one free base.

gorlbitol solution (70% N.F.), ml -10 t n siicii gi, ir igi?f li l j S8 3. The method as defined in claim 1 wherein the compound sflflchflrin, mg 1 2-d'meth -a ino-S- en l-2-ox olin-4-one Red dye (RD. dz 0. No.2), mg 10 1S l yl m ph y 82 Cherry flavor, mg 50 hydrochlofldfi- Distilled water, q.s. ad, ml 10 

2. The method as defined in claim 1 wherein the compound is 2-dimethyl-amino-5-phenyl-2-oxazolin-4-one free base.
 3. The method as defined in claim 1 wherein the compound is 2-dimethyl-amino-5-phenyl-2-oxazolin-4-one hydrochloride. 